The National Institute for Economic and Social Research (NIESR) said the economy grew 0.8% in the last three months compared with a year ago.

It is the best performance since July 2010, but NIESR attributed it to special events, including the Olympics.

The economics research group said that the UK would return to its trend growth rate of 0.2%-0.3% in the coming months.

The September output figure was flattered by the value of Olympic ticket sales, while the additional bank holiday for the Royal Wedding also reduced output in the comparable period a year ago, the NIESR said.